Kyanite and Feldspar Physical Properties
Tenacity
Brittle
  
Not Available
  
Solubility
Not Available
  
Not Available
  
Durability
Not Available
  
Not Available
  
Specific Gravity
3.53-3.65
  
2.56-2.75
  
Fracture
Splintery, Brittle, Metallic
  
Uneven, Conchoidal, Uneven, Conchoidal, Gemstones of the world (2001)
  
Cleavage
[100] perfect [010] imperfect with 79° angle between
  
two or three
  
Mohs Hardness
4-7
  
6-6.5
  
Chemical Composition
Not Available
  
Not Available
  
Kyanite and Feldspar Chemical Formula
While comparing Kyanite and Feldspar physical properties, the important data you should know is its chemical composition. Since chemical formula defines the molecular structure of the crystal, most of the physical properties like color, tenacity, solubility are governed by Kyanite and Feldspar chemical formula.
Kyanite and Feldspar Specific Gravity
Another important criteria for qualitative analysis of gemstones is Kyanite and Feldspar Specific gravity. Specific gravity is the relative density of a gemstone compared with respect to density of water. Gemologists use Kyanite and Feldspar Optical Properties during the identification of gemstone. Specific gravity of Kyanite is 2.56-2.75 whereas that of Feldspar is 2.56-2.75.